A Self-Powered Double U-Finger MME Resonator Capable of Wirelessly Capturing Abnormal Message in Smart Grid Networks

The magneto-mechano-electric (MME) coupling principle plays an important role in synchronously harvesting magnetic energy and monitoring safe operation in the distribution grid and the Power Internet of Things (PIoT). In this study, an MME resonator is presented, containing two crossed U-fingers made of piezoelectric phase-elastic beams with different lengths and magnet masses, operating in symmetric, decoupling dual bending modes. One U-finger resonating at 50 Hz serves as energy harvester (EH), while the other resonating at 185 Hz acts as current or magnetic sensor, enabling the resonator to simultaneously and wirelessly capture 50 Hz stray magnetic field (H_{AC ,50 Hz}) energy and ground fault message of power lines by injecting an additional non-grid-frequency (185 Hz) current. The EH U-finger generates an output power of 1.53 mW_RMS under a weak H_{AC ,50 Hz} of only 0.5 Oe, achieving a normalized power density surpassing current standards. While the sensing U-finger shows a high sensitivity to H_{AC ,185 Hz} with a detectability of 710 pT, even the EH U-finger is operating. The application test demonstrates the system's wireless monitoring and synchronous self-powered functions, providing stable energy for self-sensing data processing and transmission. This work introduces an efficient, wirelessly self-powered, and self-sensing method for advancements in PIoT.